1. The problem statement, all variables and given/known data In a sample of one litre of carbon dioxide at STP an average of 5 disintegrations C -> N + e + v are observed per minute. Calculate the atomic fraction of C present if the mean lifetime of this nucleus is 8267 years. 2. Relevant equations [tex]\tau[/tex] = [tex]\omega[/tex]-1 = 8267 years N(t) = N0 * [tex]e[/tex]-[tex](\omega[/tex] * t) 3. The attempt at a solution First I found [tex]\tau[/tex] = 2.607 * 1011 seconds. And really I'm at a loss of where to go next. I figure N(t)/N0 is what im looking for but I cannot solve for this without knowing the time t and I do not know where the 5 disintegrations per minute comes in. I'm not looking for an answer(already know it), i just want a little push in the right direction.